This report presents the findings of a six-part study of the informational needs of Minnesota tourists and travelers conducted for the Minnesota Department of Transportation during the second half of 1978.
The project was undertaken with the overall purpose of recommending alternative strategies for providing information to tourists about how to locate Minnesota facilities and places of interest.
This research study has attempted both to identify alternative methods of providing information to motorists and to evaluate the recommended alternatives.
The study was instigated to assess the impact of the Federal Highway Beautification Act, which calls for removal of non-conforming billboards on state and interstate roads. Many of the billboards that have been taken down advertised tourist facilities and additionally provided information on how to locate them. The premise for this study was that other means of supplying information to tourists may have been inadequate and are now perhaps even more necessary in the absence of highway billboard advertising.
Pedestrian bridges are sometimes constructed as the result of public pressures, i.e. emotional pleas for pedestrian bridges are voiced with safety used as a ploy. But, casual observation has shown that some pedestrians prefer to ignore the safety of bridges that have been provided for them, and cross highways at grade level.
The purpose of this study was to determine pedestrian crossing patterns and degree of pedestrian bridge use in areas where pedestrian bridges exist but pedestrians are not compelled to use them.
The Third Avenue North Distributor is being designed as a high capacity connection between I-394 west of Minneapolis and the downtown Minneapolis street system. It is the eastern most mile of I-394, and it will be constructed on the northern fringe of the CBD. As part of the transportation system management plan for downtown Minneapolis, three parking garages are being proposed to be constructed adjacent to, or in the air-rights of, this roadway. The garages were proposed in 1969, and in 1974, the Federal Highway Administration (FHWA) asked to have a financial feasibility study conducted along with a study to determine the impact these parking garages will have on the regional transit system. This report is the results of these studies, and includes an examination of alternative locations for the garages
This is the Executive Summary of the findings and recommendations to the Special Refuse Collection Vehicle Committee jointly under the auspices of the State Commissioner of Highways and the Director of the Pollution Control Agency.
This Executive Summary is a condensed non-technical version of the final report. It provides a capsulized summary and acts as a guide for future decisions as they relate to the issue of overweight rear loading refuse compactor vehicles under load conditions when collecting or transporting solid waste refuse. The full and final report contains the complete findings, recorded weight datum, identification of contributing factors and suggested recommendations. Readers interested in the more detailed version should refer to the final report.
On May 7, 1975, one of the main girders of the Lafayette Street Bridge over the Mississippi River in St. Paul, Minnesota, was discovered to be cracked.
Subsequently, on May 18, 1975, Dr. J. W. Fisher visited the site for a visual examination of the cracked girder. An agreement was made with the Department of Highways to investigate the cracked girder in order to ascertain the causes of the cracking and provide recommendations for corrective action-as may be deemed necessary for other details that may need attention.
The objective of this project was to conduct a state-of-the-art or synthesis research study on bridge design methods used in areas where low bearing capacity or unstable soils exist.
Over the past 15 years, foundations of certain bridges in the Red River Valley region of Minnesota have experienced detrimental degrees of movement. Settlement or shifting of piers, abutments and approach fills are common and particularly difficult to correct. The result has been that maintenance operations to keep structures in service are frequent and costly.
Three courses of action were pursued in preparing the synthesis. First, a literature search was conducted and various reports dealing with the topic were reviewed. Second, a limited field inspection was undertaken and problem sites (failure areas) were visited. Lastly, several meetings were held with persons knowledgeable about the situation and possible methods for correcting it.
Through this process, the problem was more thoroughly analyzed and a better definition of the scope of the study was developed with limits established.
One of the most serious and costly problems presently facing highway agencies is premature bridge deck deterioration. In many cases decks designed to last forty years have required major surface repairs after only ten years of service due to spalling. This spalling has been determined to be related to deicing chemical "chloride" induced corrosion of the rebars.
In response to this problem, Mn/DOT initiated a comprehensive program to restore damaged decks and protect new decks. At present, the two basic approaches to solving the problem are:
1. Prevent the penetration of chloride ions and moisture into the deck through the use of protective membranes, special concrete overlays and deck sealers.
2. Coat the rebars with epoxy to prevent chloride Ions from reaching the steel once the surrounding concrete has become contaminated.
Bridge decks were constructed or reconstructed using protective membranes, special concrete overlays and coated rebars. Testing and evaluation consist of visual observations, delamination detection, determining depth of concrete cover over rebars, electrical potential measurements and electrical resistance measurements.
This report represents data obtained through a comprehensive field study encompassing some 70 bridge decks with a variety of protection systems in place and subject to varying traffic volumes and conditions of exposure. Decks repaired also exhibited varying initial condition and extents of concrete removal prior to rehabilitation.
The basic categories of protection systems under study are as follows:
1. Membrane and bituminous overlay.
2. Special concrete overlays.
3. Coated rebar systems.
Primary testing of these systems consisted of:
1. Delamination/debonding surveys.
2. Clear cover measurement.
3. Half cell potential testing.
4. Chloride penetration testing.
5. Visual surveys.
The criteria followed for evaluation of system performance were separated into two elements:
1. System effectiveness (how well i.t does its job).
2. System durability (how., long it performs under service conditions
In August of 1976 a special study was undertaken by the Mn/DOT Research and Development Section under the existing Investigation 639 program (Bridge Deck Deterioration and Restoration). The objective of the special study was to identify sealers which would reduce chloride penetration into concrete decks and hopefully slow the corrosion process. This would in turn slow the corrosion induced spalling of the deck surface.
One of the most serious and costly problems presently facing highway agencies is premature deterioration of concrete bridge decks. The cause has now been linked to deicing chemical "chloride" induced corrosion of the reinforcement. In some cases bridge decks designed to last 40 years have required major repairs after only 10 years of service due to corrosion related "chuckholing" or spalling.
Mn/DOT has become increasingly aware of this problem during the last 5 years and has initiated a comprehensive program to resolve it. The two basic approaches to solving the problem are to:
1. Keep the salt and moisture out of the decks with protective overlays and membranes, modified concretes or sealers.
2. Protect the steel from corrosion once the concrete's protective nature has been destroyed by chloride contamination, using epoxy and zinc coatings.
Bridge decks were constructed or reconstructed using protective membranes, modified concretes and coated bars. Testing and evaluation consists of visual observations, delamination detection, chloride content testing, depth of concrete cover over rebars and electrical potential measurement.
